New Delhi, Jan 14 (IANS): Delhi's air quality saw a sudden improvement on Monday as the wind speed turned the air from 'very poor' to 'poor'. Officials, however, said this improvement is unlikely to last and the air quality would again turn 'severe'.

"The wind speed is unusually faster for this time of the year and improving the air quality rapidly. The air quality is predicted to remain poor even on Tuesday and will then start deteriorating slowly from Wednesday onwards, reaching the lower range of the very poor zone," System of Air Quality and Weather Forecasting And Research (SAFAR) said in its daily pollution analysis.

Adding to SAFAR's analysis, Mahesh Palawat, Director at private weather forecasting agency Skymet said: "From January 17, air quality will again deteriorate as south-easterly winds will flow over north India. These winds will bring a lot of humidity to the air and will turn the air quality index (AQI) to severe levels again."

"We can expect very poor to severe levels of pollution in the national capital between January 17 and 20," he told IANS.

The overall AQI in Delhi at 4 p.m. on Monday was recorded at 247 (poor), against Sunday's 'severe' air quality of 414.

In the National Capital Region (NCR), Faridabad at 256, Ghaziabad at 245, Greater Noida at 255, Gurugram at 221 and Noida at 236 also fared in the "poor" category after days of very poor or severe air.

This is the second time in this month -- after January 9 and 10 -- the air quality has improved to 'poor' after days of 'severe' or 'very poor' air quality.

In terms of general weather, the authorities have forecast light rainfall between January 21 and 24 in some parts of the national capital. Also, there would not be much fog over entire north India this week.